Conventional condoms, as shown in FIGS. 1 and 2, comprises a body 11, a sperm cell 12 and a circumferential recess 13 in the front portion. The circumferential recess 13 surrounds just the recessed edge under the glans and the sperm cell 12 extends forward in front of the sperm shooting opening when the conventional condom is worn on a penis. This kind of conventional condom is considered to have the following disadvantages.
1. The sperm cell 12 is shaped as a bowl but the connecting point with the body 11 forms a passage of the same diameter as the cell 12 so that the sperm shot therein is quite easy to flow back to the glans and further to the body 11 around the penis. When the erecting penis shrinks after sperm shooting, the chance is that the shot-out sperm may flow out of the sperm cell and along the body 11 and finally out of the opening of the condom to cause conception, or that the condom may break accidentially to permit shot-out sperm leak out of it to the result of potential conception. Besides, the penis has to be washed clean if it is coated around the shot-out sperm flowing back in the body 11.
2. Air may be forced in the vagina by the action in the intercourse process, and if the forced-in air is not exhausted out to balance the inner and the outer pressure, the intercourse may not be smoothly carried on and both persons may feel unpleasant. It is natural that a woman gives out secretion fluid during the intercourse to keep her vagina wet enough for smoothing the action, and the circumferential recess under the glans serves for air ventilation and exhaustion of secretion fluid. As a conventional condom has its body 11 formed cylindrical to have the same diameter from the top to the bottom, it can not be useful for air ventilation and exhaustion of secretion fluid when it is worn on the penis, because the circumferential recess under the glans can be blocked. Sometimes the condom may contain some air if a user is too hasty in wearing it, and the circumferential recess may lose its function such that the intercourse cannot go smoothly enough to get satisfaction or some harm may occur if worse. And the outer and the inner pressure do not balance so that the condom receives bigger friction than otherwise, and thereby its breaking opportunity largely increases to the result of lessening contraception effectiveness. The cause is the loss of the functions for air ventilation and exhaustion of the secretion fluid that the circumferential recess should have.
This invention has been devised to improve the above-mentioned disadvantages of conventional condoms.